Best Way??

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Tganks Guys,
For the help, now have to decide if I want to use fuse or breakers betwween the battery/CC and batteries.

I'll post photos during the build and show the results etc.

What is the post that shows ALL the solar setups of the guys??

Tia,
Don

OK Guys,
Next step,
if I am forgetting or missing ANYTHING, feel free to advise me.

I have the 2-8ga parallel wires comning from the panels to the reefer vent and dropping straight down into the OEM electrical bay where the MS MPPT CC is going to be installed.

Do I need to do anything special to attach the panel wires to the charge controller? Can I attach the panel wires directly to the CC?

From the CC, I can then run the 2awg wires to the 4-GC batteries,
Do I need a fuse between the CC and batteries?

Tia,
Don

Ca Traveler,

Thanks for the info, I thought,I had misread the info and was getting more confused etc.

As for the 4 GC batteries underneath and tucked up inside the frame rails,
Yes, it is the only way I have of carrying the batteries needed for the solar install.

I already have 2 HD Marine batts on the toungue, that will used for the trolling motor use, (which are now used to run the house/ furnance etc), untill I finish this major solar install.

Seeing that I have NO storage areas to use for batteries, I am left with no other choice, the only negative I have found for the TH, so far.
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Jim,
Thank you for the info.

Tia,
Don

More on derate: The CC manual shows 60A to 140V array voltage. The amps then drop to 0 at 150V. 150-155V is listed as over voltage. So best to stay under 140V. Not a factor for the OPs 2x2 array.

And when the heatsink temperature reaches 80C the output amps will then drop to 0A for 90C. Roasty toasty at those temps.

nvreloader,

Are you still planning for that big battery bank under the rig? Rather unique I thought.

nvreloader, Your link to the calculator shows 130.5V for 3 panels in series. For 4 panels in series this is about 172V. Notice that I said 4 panels in series. So series is not possible for you as you would exceed the CC max VOC. And you're using the calculators output and planning on the 2x2 serial/parallel setup and it is ideal for your 4 panels.

Derate: The maximum watts for the CC is 800 and your panels are rated for 880. The CC will handle 880W and even more. But if the CC output every goes above 60A it will be clipped to 60A or derated to 60A. Considering normal solar losses, wiring losses and CC losses I doubt that you'll reach 60A output and if you do then it will likely be short lived.

Don

I have one 220w panel and run it with a inexpensive yet functional 20a MPPT controller.

BFL

It could be a number of things. The mono is better at producing Voc but its Isc, Imp, Vmp and footprint are all smaller than the poly. The Mppt is working because I'm seeing 12a with a panel rated at 8.09a Isc.

Maybe a different controller would extract more out of the higher voltage, maybe not. I've come to the conclusion that mono IS more efficient but only because it can hit its ratied output with a smaller foot print. Great for grid tied, on a roof with full sunlight. Not so good for us RV'rs when we need the amps in low light. There the larger footprint of the poly panel has the advantage.

Guys,
Bear with me on the following questions, I am going to ask.

Jim,
Thank you for the info on your Canadian 220w panel, do you have more than 1 hooked up, if so how are your panel wired?

The average elevation where we spend our time at is right around 5000' average and the lowest temps we have observed (so far) is MINUS 22* for several days with 4+ snow on the ground and the wind averaged 10-15 mph and 1 day it was over 50-60mph gusts.
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Ca Traveler,
How did you come up with your info that my panels are 43v x 4 = 172v going into a 150v MPPT CC.

The spec's of MY panels are,
4-Canadian SC6P-220watt Panels with the following spec's,
Pmax=220W
Voc =36.60V
ISC =8.09A
VMP =29.30V
Imp =7.52A
Voc-coef =0.1281V/C
Noct =45.00C
15A fuse rating/series,

Minimum low Temp of Minus -22* and average High 100*

The MS calculator shows different info, for 2 panels in series for/per 2 strings and 2 strings in parallel, it states that this is a perfect setup, if I am reading and UNDERSTANDING this info.

I am not arguing or doubting your/anyones info, OK,
but attempting to understand how the info was arrived at. :?

I do NOT know what "derating" means when you guys are talking about it for these panels. :@

Tia,
Don

JiminDenver wrote:
The best I've seen out of my panel at a mile of altitude has been 12.75a (high noon, subfreezing) so I don't think he will be being derated too often.

I thought the sometimes low amps on MPPT was from the panel getting too hot and losing voltage to make amps from. But here we have the panel at full voltage (after dropping from higher than that due to warming) and it is still below in amps.

There was the mono vs poly thing but I thought the voltage/MPPT factor would apply to both. So obviously I still don't understand MPPT.

Can anybody explain what JiminDenver is seeing there? Thanks.